Australia batsman David Warner was left “shaken up” after hitting a net bowler on the head with a powerful drive, captain Aaron Finch said.
His visibly concerned team-mates had to halt their practice session at The Oval while medics treated the bowler – understood to be a local cricketer named Jaykishan Plaha.
He was taken to hospital as a precaution after receiving treatment.
Defending champions Australia face India in a World Cup match on Sunday.
“The net bowler has been taken to hospital as a precautionary measure because it was a head injury,” International Cricket Council venue manager Michael Gibson told reporters.
“He was conscious and smiling as he was taken off.”
Finch added: “Dave is obviously pretty shaken up. The young guy is in pretty good spirits at the moment. He has obviously been taken to the hospital to be assessed that everything is OK.
“It was a pretty decent hit, so hopefully everything goes well for the youngster and he is up and running shortly.”
In 2014, Warner, 32, who returned to playing international cricket in April after a year-long ban for ball-tampering, was playing for South Australia when his team-mate and close friend Philip Hughes was fatally struck on the head by a ball while batting.
In July 2017, Nottinghamshire bowler Luke Fletcher was struck on the head by the ball during a T20 Blast match, ruling him out for the season.
At the time, the 30-year-old said he was “lucky to still be here” and that he “dodged a bullet”, after he was hit by a straight drive from Birmingham Bears batsman Sam Hain.
“It’s quite rare that somebody gets hit, it’s really unfortunate,” Finch added.
“Our own medical staff and the paramedics on the ground did a great job.”
